Whenever I get a message or an email or a comment regarding
unsuccessful bridge circuits, it’s usually along the lines of no output being
observed, the MOSFETs getting hot, or everything just getting damaged or
blowing up. When I was in the preliminary stages of bridge design, I also had
repeated failures. I had circuits blowing up. I had circuits just not working,
no matter what. I’ve written on my blog about one such experience of mine. You
can read it here:http://tahmidmc.blogspot.com/2012/10/magic-of-knowledge.html

In this article, I’ll talk about the first things you should
do if your attempts at designing a bridge circuit have gone up in smoke or if
you’re designing a bridge circuit and want to ensure everything has been done
properly.

Another thing I should mention is that, in almost all cases
of people asking for help, the bridge driver (the high-low side driver) has
been the IR2110 (or similar, such as IR2112, IR2113, etc). Remember that most
bootstrap-based high-low side drivers function in pretty much the same way. So,
I’ll talk about the driver in general here. I had, however, written a tutorial regarding the IR2110. So, if you're interested regarding that check out:

The first thing to do is to check everything over and over again. I know it's cliched and it's probably the most repeated thing you’ve heard, but it's also the least
appreciated or followed. One missing
connection (or an extra one too, eg a short) could be the cause of all the mayhem.

1) Firstly, check the connection of the bridge itself. Ensure
that all the MOSFETs are connected correctly.

2) Check the power connections to the drivers. Make sure that
the supply voltage is within acceptable bounds. Ensure that you have small
decoupling/bypass capacitors (0.1µF ceramic capacitors) along with larger
filter capacitors (for example, 10µF electrolytic capacitors). Use the 0.1µF
capacitors across all power lines.

3) Check the connections to the drivers, ie the driving signals
coming from the PWM controller, microcontroller, etc. Make sure that the
signals for the high-side MOSFET and the low-side MOSFET of one leg of the bridge don’t
overlap. If, in any way, both the high-side and low-side MOSFET turn on
simultaneously, this will be a dead short-circuit. Expect some ka-boom and
smoke. Use an oscilloscope to ensure that the signals don’t overlap.

4) Check the bootstrap circuitry. Make sure you’re using the
proper diodes – ultrafast diodes when required. Make sure your bootstrap
capacitor is large enough, but not too large. As I had previously mentioned,
there is a simple guideline I follow. For low frequencies and high on-times,
use large capacitors. 47µF to 68µF could be used for 50Hz/60Hz, for
example. For higher frequencies, eg 30kHz, use smaller capacitances, eg 10µF.

5) Check the connections from the drivers to the bridge
MOSFETs. Ensure that you’ve placed a series gate resistor between each driver
output and MOSFET gate. Ensure that you’ve connected the virtual ground
(obtained using the bootstrap capacitor; for example, this is the pin 5 – VS –
of the IR2110) to the corresponding high-side MOSFET source. Check that you’ve
connected the high-side output of the driver to the high-side MOSFET gate and
that you’ve connected the low-side output of the driver to the low-side MOSFET
gate.

6) Check that you have placed a gate to source resistor between
the gate and source of each MOSFET. I always use a 1kΩ resistor. If you have a
number of MOSFETs in parallel, have a gate to source resistor for each MOSFET.
Choose the resistance such that the combined resistance is about 1kΩ.
For example, if you have three MOSFETs in parallel, for each MOSFET use a 3.3kΩ
resistor. This will give a combined resistance of 1.1kΩ (you can use 3kΩ
resistors to get a combined resistance of 1kΩ).

Read here about one of my experiences where I damaged loads of drivers and MOSFETs all due to the lack of gate-to-source resistors:

7) Ensure that you have used the same ground for the drivers
and the controller generating the drive signals (microcontroller, PWM
controller, etc) and the bridge. Most (all that I’ve used) bootstrap-based
high-low side drivers are non-isolated drivers. The input and output stage are
not isolated from each other. Hence, the driver must share the same ground with
both the input stage (which is the microcontroller, PWM controller, etc) and
the output stage (which is the bridge that is being driven).

If you have a faulty bridge design and are making changes to
it, replacing some components to try again, I suggest you get rid of everything
and construct the circuit again using no parts from the old circuit. A faulty
MOSFET can damage the driver and vice versa. A faulty driver may damage other
parts and so there may be other damaged parts on your circuit that you don’t
even know are damaged.

If you follow these tips/hints, you should be able to
successfully design bridge drive circuits with no problem. Following these
tips/hints will also help you solve problems in any existing bridge drive
circuit.

after reading ur tutorials i have some questions on deadtime mechanism of Mosfet driving for full bridge or half bridge SMPS circuit.How can one ensure the dead time by programming a micro-controller?? Is there any hardware available which ensures the dead time automatically for me????

It will be very helpful if u make a tutorial about dead time mechanism and how to create dead time using mcu programming.

Dear Tahmid Can you please give some idea for adjusting sine PWM fundamental frequency with ADC1 (50Hz) and voltage using ADC 2 with look-up-table method. I tried but it was not 50Hz some unknown frequency for posting the waveform I don't have CRO presently. I want to go to my college presently all are in vaccation can u give some so that I will simulate in PROTEUS

Dear TahmidCan you please give some idea for adjusting sine PWM fundamental frequency with ADC1 (50Hz) and voltage using ADC 2 with look-up-table method. I tried but it was not 50Hz some unknown frequency for posting the waveform I don't have CRO presently.I want to go to my college presently all are in vaccation can u give some so that I will simulate in PROTEUS

good one ...i almost approximate same as this method~~ .... could i ask u supply 300V ... ..POINT A out and POINT B out u connected to Ferrite Core Transformer Then generate Sine Wave ? Or u connected a Iron Core Transformer....I not quite sure about the ferrite core transformer..but for me just use the Iron Core Transformer..

Tahmid do u have any guide tutorial to teach real practical to winding own transformer ...i hope got the real picture for guide step by step ..not only the theory Concept for guide the Winding Ferrite core Transformer ...i appreciated ur everything in this website

In engineering, there are good attempts and there are loose-shots....well, the IR21XX series (particularly 2110)is one such. I dont know who uses it, havent seen it in any successful design or commercial product so far in the market. The low side will work fine...But...the Hi-side mosfet will just never stop ringing...no matter what you do....Welcome to the real world. So how do they do it in inverters/converters 500W or above ?.... It takes a different approach. (mail: corollaups@gmail.com)

IR2110 is actually widely used. There are many successful designs using IR2110. Why it isn't used in many commercial products is probably more due to its relatively high cost, rather than because it is flawed. It is certainly used in high power circuits.

Hey bro, awesome blog. Can you show how to design an embedded controller (PIC16F690) which is powered by a single 0.47F 5V supercapacitor. The MCU should be able to turn on and off, and only relying on the capacitor as its power source.

The first thing that came to my mind when I read this was that you have to find a way to deal with the capacitor's exponential discharge. With a battery, the voltage doesn't drop too much. A 6V battery, when almost fully discharged, will likely still have >4V EMF. However, the voltage across the supercapacitor will drop all the way down to 0 when fully discharged.

hi tahmid, how to design output filter after hbridge to get a pure sine wave?my hbridge is working fine and is driven by spwm,but when i connect my filter ,the mosfets of hbridge blown out,, i have tested my hbridge output with resistive load ,and that was working fine,, can u plzz tell me where the problem could be?

You need to use an LC filter. Upload the circuit of the output filter you're using, along with the diagram of the bridge stage, driver stage and the SPWM generation stage. I'll take a look to see where the problem lies.

Glad to found your blog. It's very helpful and informative. By the way, I am working on DSP controlled inveter using IGBT. How about using optocoupler first then IR2110 driver for IGBT? will it be possible?

does it mean that i need to have 4 different isolated power supply for each of the transistor side of opto-coupler since i am creating full bridge circuits? by the way i am using HCPL4506 opto-coupler and IR2181 for full bridge drive..will IR2181 be a replacement for IR2110? I have a 3.3v pwm signal from DSP.

pls my output is around 64vac instead of 240vac .my dc to dc side is 348vdc.pls what could be the problem with my h bridge? am using irfp460z at d h bridge side.wen i input 12vdc to my h bridge ,it produces 14vac at 50Hz but with 348vdc it output 64vac.pls help.

Yes, most circuits that are designed to drive MOSFETs can drive IGBTs. So, you can drive IGBT with the mentioned circuit.

For more information, take a look at this:"Using the high-low side driver IR2110 - explanation and plenty of example circuits"http://tahmidmc.blogspot.com/2013/01/using-high-low-side-driver-ir2110-with.html

hello tahmid,have built a h bridge based on your circuit here using ir2110.it works,thanks .but am having a problem currently.when i join my dc to dc side together with the h bridge.my ir2110 get damage with my mosfet(just two of mosfet) but when i start the dc side first then connect the h bridge,it will work.pls what could be the problem.my dc side is also based on your circuit too

Assalamo Alikum Tahmid.. Brother your work really helps us a lot while attempting different circuits. I have a problem of Collector-Emitter voltage drop in IGBT. My circuit is working fine but i m getting 4-5 volts less than the applied DC voltage. Please help me

thanks for sharing information .....i am designing smps using half bridge topology in which vs of ir2110 can not be connected in between mosfet so in that case driving high side mosfet is difficult so help me .....how to drive high side mosfet without vs connected in between mosfet....thanks

Can you help me please?I want design this circuit but instead 300VDC I will use a 900VDC HV capacitor, the main idea is discharge the Cap in two phases, 7ms of positve period and 7ms in the negative one. Regards

I came up with the h bridge for my application by referring your tutorials. I am getting output for low voltage loads. When i am giving 220v dc as load voltage and my load is actuator coil. The ground side is getting damaged and no switching occurs. I tried with 60w bulb as load and connected the 220v ground to driver ground through a resistor. By doing this the bulb glow while switching and there is some small head it resistor while i performed the switching continuously....

Hi friend, I have repeatedly failed in successfully implementing the IGBT half bridge using IR/IRS2110. I have chosen all the component values as accurate as you mentioned in your blog. I am using FGA25N120ANTD IGBT for the half bridge.I want to show the picture of my circuit board and corresponding waveform.If you kindly give me your e-mail,it will be very helpful to me.

Hello Tahmid. Your posts has been helpful. I'd love to ask what value would you recommend for bootstrap capacitor for IR2110, the low side mosfets are given the 50Hz while the high side is modulated with SPWM with a frequency of 2500Hz. Thanks...

I have connected. Low& high side driver using ir2110 for full bridge frequency 20kHz using arduino but I am not getting output at high side. Supply of 5 volt and 12 volt. Are given at Vcc and Vdd. Is the ground from pin 2 different from. Ground from capacitor could you help me in this

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About Me

I am Syed Tahmid Mahbub, from Dhaka, Bangladesh, born on August 1, 1994.
Electronics is my passion and from class V, I have been learning electronics. I learnt and worked mostly on SMPS, power electronics, microcontrollers and integration of microcontrollers with SMPS and power electronics. I've used PIC and AVR microcontrollers - PIC 10F, 12F, 16F, 18F, 24F, dsPIC 30F, 33F, PIC32, ATmega and ATtiny, integrating them with various SMPS and power electronics circuits.
I have completed my Bachelor's degree from Cornell University (Class of 2017) in Ithaca, New York, USA, majoring in Electrical and Computer Engineering (ECE).
I am a member of the forum www.edaboard.com, where I am an "Advanced Member Level 5" (the highest level attainable) and also the forum allaboutcircuits.com, where I am a "Senior Member". I post to help solve electronics-related problems of engineers and engineering students from all over the world.
I love watching and playing cricket and football (soccer), and listening to music.
I am now a hardware engineer at Apple in Silicon Valley, California, USA.